RU2442820C1 - Polyfunctional additive to engine oils - Google Patents

Abstract

FIELD: chemistry

SUBSTANCE: The invention is used in oil production for highly boosted petrol engines, turbocharging diesel engines and their further operation. The additive contains a 50% solution of the mixture of amine salt and dialkyltiophosphoric acid amide solved in oil - ADTF additive and tetraalkyl thiuram disulphide taken with the ratio to ADTF ranging from 1:3 to 3:1, whereas the mass portion with the atomic ratio of sulphur to phosphorus in the additive ranges from 3,25 to 11,55.

EFFECT: improved anti-oxidising properties while retaining anti-wear and anti-friction properties, at the same time reducing the amount of sulphur, phosphorus and sulphate ash content in the oil, which increases the interval between oil changes and the engine working capacity between repairs.

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Description

The invention relates to the field of petrochemistry, and more particularly to additives for motor oils that improve antioxidant properties, as well as reduce metal wear in friction units of internal combustion engines, and can be used in the manufacture of oils for highly accelerated gasoline engines and turbocharged diesel engines and their further operation.

One of the traditional antioxidant additives to motor oils is zinc dialkyl dithiophosphate, which is widely used in the package of additives for motor oils in modern production in Russia and abroad [Papok K.K., Ragozin N.A. Dictionary on fuels, oils, lubricants, additives and special fluids. Chemotological dictionary. - M .: Chemistry, 1975, p.79]. This compound also has anti-wear properties and, in part, anti-corrosion effect, due to which it is considered a multifunctional additive. However, it is known that phosphorus atoms have a poisonous effect for catalytic afterburners of exhaust gases. Sulfur in the composition of the additive negatively affects the ecology of the environment. Metal atoms in additives, in this case zinc, increasing the sulfate ash content of oils in general, lead to the formation of solid chemical films on the surface of metal parts [Spikes N. The history and mechanisms of ZDDP // Tribology Letters, vol.17, No. 3, 2004, p. 469-489]. The above leads to an intensive search for solutions aimed at reducing additives in the composition of the package (composition) of compounds that adversely affect the environment.

The authors were faced with the task of developing such a multifunctional additive to motor oils that would increase the antioxidant properties of oils while maintaining their level of antiwear and antifriction properties with a significantly low content of sulfur, phosphorus, and metals in them.

When analyzing patent and scientific and technical information, technical solutions were identified that partially solved the task.

From WO 2007084407 [C10M 141/10 of 07.26.2007] a composition is known containing zinc dithiophosphate as an anti-wear additive, alkylated organosulfur compounds, and anti-wear compensation compounds contain alkylated sulfur-containing aromatic compounds in which there are no phosphorus atoms and have lowered to 0.25 wt.% sulfur content. The disadvantages of the known composition include the presence of phosphorus and metal atoms in zinc dithiophosphate, which leads to poisoning of catalytic afterburners and increases the adverse effect on the environment of the sulfate ash content of the oil.

A composition having anti-wear properties and consisting of zinc dithiophosphate, a sulfur-containing compound and an ester formed by a polyfunctional alcohol and polyfunctional carboxylic acid is known from WO 2005111179 [C10M 129/00 of 11.24.2005]. Despite the high antiwear activity of the composition and the low phosphorus content in it (0.05 wt.% In comparison with 0.1 wt.% In pure zinc dithiophosphate), it includes a metal and is negatively characterized by a significant content of sulfur atoms (up to 0.5 wt. .%) and phosphorus (up to 0.1 wt.%).

A composition is known from WO 2006107441 [C10M 129/00 dated 12.10.2006] in which phosphorus-containing compounds (acidic mono- or dialkyl phosphates) are used as antiwear component with phosphorus content from 0.5 to 2.5 wt.%, As anti-seize the component is sulfur-containing compounds (sulfonated olefins, preferably isobutylene) with an atomic ratio of sulfur to phosphorus in the range of 3.2-3.9, and nitrogen-containing compounds (aliphatic or heterocyclic amines) as an antioxidant. The disadvantages of this composition, in addition to the high content of phosphorus and sulfur atoms in the composition of additives, include increased acidity due to the presence of phosphorus-containing components, which in turn cause metal corrosion.

As an additive to oils, a composition is also known including a phosphorus-containing compound (phosphoric acid, its esters or salts, including those containing sulfur atoms) and nitrogen-containing compounds, for example thiocarbamates [US 2006223721 C10M 137/00 of 05/10/2006]. The disadvantage of this additive is a complex synthesis of components and includes, for example, the interaction of dithiophosphoric acid with hydrogen peroxide in a solution of alcohols consisting of 40% isopropyl alcohol and 60% 4-methyl-sec-amyl alcohol, which limits the use of the proposed composition.

The closest in technical essence to the invention and taken as a prototype is the additive ADTF [Chulkov P.V., Chulkov I.P. A Brief Dictionary of Petroleum Products. - M .: Polytechnic, 1997, p.326], which is a product of the interaction of dialkyldithiophosphoric acid and amine - a 50% solution of a mixture of amine salt and dialkyl dithiophosphoric amide in oil. Mass fraction of nitrogen is not less than 0.2%, phosphorus - not less than 3.3%. The alkyl radical in the ADTP component includes the number of carbon atoms from C ₄ to C ₁₂ . This additive is metal free and has effective antioxidant and antiwear properties. The disadvantage of the prototype is the increased (more than 3.3 wt.%) Phosphorus content, which negatively affects the operation of the afterburning catalyst.

The technical result of the invention is the increase of antioxidant properties while maintaining anti-wear and antifriction properties while reducing the content of sulfur, phosphorus and sulfate ash in motor oils.

The specified technical result is achieved by the fact that in the known composition containing the product of the interaction of dialkyldithiophosphoric acid and amine (50% solution of a mixture of amine salt and amide of dialkyl dithiophosphoric acid in oil - ADTP), according to the invention additionally contains tetraalkylthiuram disulfide (TDS), taken in a ratio of 50% a solution of a mixture of amine salt and dialkyl dithiophosphoric acid amide in oil from 1: 3 to 3: 1 in a mass fraction with an atomic ratio of sulfur to phosphorus in an additive in the range of 3.25-11.55.

Tetraalkylthiuram disulfide is the product of the interaction of di (2-ethylhexyl) amine with carbon disulfide and sodium hydroxide and at 20 ° C it is a liquid containing 20.4 wt.% Sulfur and 4.25 wt.% Nitrogen. The alkyl radical in tetraalkylthiuram disulfide contains C ₄ to C ₁₆ carbon atoms. [Shkhiyants I.V., Markova E.I., Voevoda N.V., Sher V.V., Sanin P.I. The study of antioxidants such as metal dialkyl ditocarbamates // Petrochemistry, Volume 11, No. 6, 1971, p. 919]. The use of TDS is known [S. Kumar, NNRoy / Wear, - 1997. - v.209. - p.1-7] as part of a multifunctional oil composition in combination with bis (aryl / alkyl) thiuram disulfide, bis (aryl) xanthate and (aryl / alkyl) dithiocarbamate. The range of the atomic ratio of sulfur to phosphorus is 3.9-4.9. The effect of the compounds used is pronounced in the load region of 315-500 N (extreme pressure properties). However, a narrow range of the atomic ratio of sulfur to phosphorus creates technological difficulties in its implementation, and its slight deviations to the lower side lead to a decrease in the antioxidant properties of oils.

The authors are not aware of the use of TDS in motor oils in combination with other components. The authors conducted a study of the technical effectiveness of the combination of two components: ADTF and TDS.

To determine the optimal concentration of the components in the additive, its experimental samples were prepared. The composition of the experimental samples of the additive is presented in table 1, and their characteristics according to the content of phosphorus and sulfur are shown in table 2.

Table 1 The composition of the prototype additives Additive Components Sample number and additive component ratio one 2 3 four 5 6 7 Tds 0 0.2 0.25 0.5 0.75 0.8 1,0 ADTF 1,0 0.8 0.75 0.5 0.25 0.2 0

table 2 Characterization of Prototype Additives Components included in the composition Content% Atomic ratio R S S / p DF-11 0.0938 0.1942 2,0703 Sample 1 0.0640 0.1325 2,0703 Sample 2 0.0480 0.1500 3.1250 Sample 3 0.0480 0.1560 3.2500 Sample 4 0,0320 0.1674 5.2312 Sample 5 0.0160 0.1848 11,5500 Sample 6 0.0160 0.1883 11,7687 Sample 7 out 0.2022 -

The ratio of ADTF and TDS in the multifunctional additive is selected in the range from 1: 3 to 3: 1, giving the highest technical result. The inventive multifunctional additive is introduced into the oil in an amount of not more than 1 wt.%, Which provides increased antioxidant properties while maintaining anti-wear and antifriction properties while reducing the content of sulfur, phosphorus and sulfate ash in the oils.

To confirm the claimed ratio of the components in the additive and to determine the effectiveness of their action in oil, the prepared samples (Tables 1, 2), in comparison with the applied antioxidant and antiwear additives DF-11, were tested to evaluate the antioxidant, antiwear and antifriction properties.

Table 3 presents the results of high-temperature oxidation of pilot samples of the additive in oil, carried out at 180 ° C for 20 hours and sparging the oil with air at a rate of 5 × 10 ^-3 m ³ / s with a rate of analysis of oil samples every 5 hours according to STO 08151164 -012-2009.

The optical density was determined using a photocolorimeter, the photometric contamination coefficient in accordance with OST 24.060.09-79, the kinematic viscosity in accordance with GOST 33, the acid number in accordance with GOST 11362.

As can be seen from the results of testing a multifunctional additive in oil, samples 3-5 are optimal for improving the antioxidant properties. The best effect was shown by a pilot oil sample with 1% additive sample No. 4. Samples 1, 2 and 6, 7 are inferior in antioxidant properties to samples 3-5.

Tests of prototypes to assess anti-wear and antifriction properties (tribological characteristics) were carried out according to GOST 9490. As shown by the test results (table 4), the proposed multifunctional additive (samples 3-5) in oil provides anti-wear and zinc comparable with zinc dialkyldithiophosphate (DF-11) and antifriction properties, and their indicators do not exceed permissible values.

Table 4 The results of the evaluation of the tribological characteristics of the samples The composition of the prototypes of the composition Antiwear properties Antifriction properties The diameter of the wear spot, D _u , mm ^* Coefficient of friction, f (60 min) ^** A mixture of I-20 and I-40 (0.5: 0.5) 0.92 0.154 Same with: 1% DF-11 0.392 0.138 1% of sample 1 0.706 0.145 1% of sample 2 0.462 0.131 1% of sample 3 0.429 0.139 1% sample 4 0.435 0.135 1% sample 5 0.449 0.140 1% sample 6 0.680 0.143 1% of sample 7 0.706 0.145 ^* No more than 0.45 mm allowed ^** No more than 0.140 allowed

As a result of testing prototypes of the proposed composition, it was found that the additive composition consisting of a mixture of TDS and ADTP in a ratio of 0.5: 0.5 with an atomic ratio of sulfur to phosphorus of 5.2312 (sample No. 4) is optimal in composition and level of properties.

Tests of a prototype oil containing 1 wt.% Additives in the stated proportions (sample No. 4), in comparison with oil containing 1 wt.% Of the commercial additive DF-11, were carried out according to the motor method IKM-40 (GOST 20457) evaluating the antioxidant properties (table 5).

Table 5 Assessment of antioxidant properties of oils Name of indicator Norm according to the method Sample with DF-11 Prototype Antioxidant properties kinematic viscosity increase at 50 ° C during the test,% No more than 50 34 23 Anticorrosion properties The loss of mass of the liner of the lower connecting rod head, mg No more than 25 19 fourteen

The test results showed that the prototype oil containing 1 wt.% Additives in the stated proportions (sample No. 4) surpasses the oil sample containing 1 wt.% Commodity additives DF-11 in antioxidant properties (Table 5, line 1) and not only preserves the level, but also surpasses it (Table 5, line 2) in terms of anticorrosion properties.

The application of the invention will allow the production of motor oils for highly accelerated gasoline engines and turbocharged diesel engines with improved antioxidant and anticorrosive properties while maintaining the level of antiwear properties and at the same time reducing sulfur, phosphorus and sulfate ash, which helps to increase the time for changing the oil in the engine and its overhaul life.

Claims (1)

A multifunctional engine oil additive containing a 50% solution of a mixture of amine salt and dialkyl dithiophosphoric amide in oil, characterized in that it additionally contains tetraalkyl thiuram disulfide, taken in a ratio of 1: 3 to 3: 1 by weight in relation to a 50% mixture solution the proportion at an atomic ratio of sulfur to phosphorus in the additive in the range of 3.25-11.55.